Time fuse



May 19, 1925.

A. s. MILLER TIME FUSE Filed June 25. 1924 a?! vil v v v v f I w f w ho e M- m an. W

Patented May 19, 1925.

ALTEN S. MILLER, OF BALTIMORE, MARYLAND.

TIME FUSE.

Application filed June 25, 1924. Serial No. 722,369.

To all whom it may concern:

Be it known that I, ALTEN S. BIILLER, a

citizen of the United States, residing at Bal-' timore, in the State of Maryland, have invented certain new and useful Improvements in Time Fuses, of which the following is a specification.

This invention relates to time fuses for explosive shells, and particularly to the construction of the timing rings therefor.

In my allowed application, Serial No. 685,229, filed January 9, 1924, I describe and claim a method of and apparatus for controlling the rate of burning of time pow- 5 der trains. This method involves the maintenance of a constant absolute pressure on the burning train by the use of a constant vent orifice for the gases evolved in burning, and the success of the method is dependent on the evolution of the gases at a constant rate. This is easily accomplished with the single time ring shown in that application, but cannot be readily accomplished with the conventional type of double time ring, for the reason that in certain adjustments of the rings the train in the first ring will continue to burn after the train in the second ring has commenced to burn, with a consequent increase of the rate of evolution of gases. This arises from the fact that the flash hole from the concussion primer to the first ring and the fiash hole from the second ring to the charge are in a fixed angular relation to each other.

The present invention relates to a construction of the rings such that each" ring will transfer the flame to the next just as it burns out, and not before. This permits the use of a multiple ring construction in which the rate of burning can be successfully controlled by a fixed orifice in the manner characteristic of said prior application. The invention thus increases the utility of my prior invention,particularly in its application to long range shells. and is also of general utility in any case where the evolution of gases at a constant rate is necessary or desirable.

Generally stated, the invention involves the construction of the fuse so that the front portion of the body of the fuse, which car ries the concussion primer, is swiveled and may be rotated relatively to the shell, and so that the first ring turns with such forward portion of the body. Thus the flash from the concussion primer is transmitted to the beginning of the train in the first ring in all adjustments. For all timing within the full time range offered by the first ring the flame is transmitted to the charge in the shell from the first ring through the pellet at the beginning of the second ring. For all timings within the added range offered by the second ring the two rings are adjusted relatively to each other so that the flame is transmitted from the end of the first ring to the pellet at the beginning of the second, and the two rings are so adjusted relatively to the shell that the flame is transmitted to the charge after the train in the second ring has burned the desired distance.

This'inventive concept may obviously be embodied in fuses having more than two rings, but as two show the principle and ordinarily are sufiicient I have chosen this embodiment for illustration.

The accompanying drawing shows the im-' proved fuse in longitudinal axial section, as it appears when mounted on the nose of a shrapnel shell.

A part of the casing of the shell appears at 5 and is closed at its forward end by a plug 6 threaded therein.- The body of the fuse consists of two portions 7 and 8. The rear portion 7 is threaded into the plug 6. The front portion 8 of the body is swiveled on the rear portion 7- and is retained in place by means of a bolt or rivet 9. The usual chamber for the magazine charge 10 is formed in the rear section 7 of the body and to this leads the usual passage 11 containing an ignition pellet 12.

Two time rings 13 and 14 are provided. 1

The rear ring 13 is swiveled on the rear portion 7 of the fuse body and is provided with a powder train 15 and with an ignition pellet 16 at the beginning of that train.

In one adjustment of the ring 18 relatively to the rear portion 7 of the body, the flash may be transmitted from the pellet 16 to the pellet 12. In other adjustments the flame must follow the train 15 from the pellet 16 to the pellet 12.

The forward timing ring 14 is mount-ed on the forward portion 8 of the fuse body and is keyed or splined thereto by means of a key or feather 17 so as to turn therewith.

The ring 14 is provided with a powder train 18 so arranged that the angular adjustment of the ring 14 relatively to the ring 13 permits the flame to be transmitted to the pellet. 16 from anyHdesired point in the length of the train 18.

Mounted in the forward end of the'portion 8 of the body is the concussion plunger 19, which is retained by the usual resistance ring 20 and which carries the usual concussion primer 21. The firing pin for the concussion primer-is shown at-22 and may conveniently be formed on the head of the bolt or rivet 9.

"Agfiash hole 23 transmits the flash from the concussion primer2ldirectly to the beginning of the train '18 in the ring 14. The flash hole'23 is-formed partly in the ring 14 and partly in the-portion'8 of the body, but since these two parts turn together a constant registry is had. In effect, the ring lt'and the port-ion 8 of the" body are one piece but it is more convenient to manufacture' them as two separate pieces connected together.

The concussion primer structure is housed by thecap=24 andthiscap is providedwith vent ports 25' for the powder gases evolved by the burning trains; The ports 25-lead to a n'orifice 26 Whose size is determined by considerations hereinafter outlined, and this orifice "serves to E maintain a constant pressure onthe' burning powder trains so long'as the powder gases'are evolved-at-a substantially constant rate.

For convenience "-in manufacture; the ori fice '26 is formed in a plug 27 which is threaded into the forward end of the cap 24. A false cap' 28 having relatively large vent; ports 29 isalso threadedcnto the forwardendof the cap 24:.

The size-of the orifice '26 is determined by thefollowing' considerations:

'If a gas or -a=mixture of gases is di charged under a constant head pressure through a'fixed orificefthe'rate of flow-will vary-as an inverse function of the pressure on the discharge side of the orifice, provided this pressure be above a {definite critical value, which, expressed 221$ a function otthe head pressure, is a constant for the particulargas. Below 'suchcritical value changes of=pressure' on thedischarge'side do=not a'ffeet the rate of flow.

To take advantage of this phenomenon, I so coordinate'the train and-thesize of the orifice 26 that the train burns under a =constant absolute pressure,= which is sorelated to the maximum atmospheric pressure that all variations inatmospheric pressure occur below such critical value and hence have no effect'upon the rate of'"flow through'the ori- 'fice 26. This characteristic action of the vent26 is claimed in -myprior application above identified and hence is not broadly claimed herein.

Obviously, itis essential that the powder trains evolve gases at a definite quantity train,

bot-hmounted inrsaid combined membery.

from the pellet 16 is transmitted directly across thering tothe-pellet 12, the train 15 in the rear ring 13 is functionless for it can :befignited and burned only after or simultaneously with the ignition of the magazine charge 10. WV ith' the ring 13 in this position the ring 14E may be adjusted relatively thereto so that any-desired portion of the train 18 may beburned before the pellet 16 is ignited.

F or'-longer ranges,'the rings' 13 and 14 are adjusted relatively' to each other sothat the pe'llet 1-6 registers with the end of the train 18 and hence is ignited just'as this train burns out. VVith" the ringslS and-14c so relatively adjusted, I it is possible to adjust both rings relatively to' the *body portion 7,-sothat the pellet- 12 is ignited after any desired portion of the train v1-5 has burned. In this way,it is possible to get any time adjustment up to that afi'orde'd by' the successive burning of the two trains'and yet at no' time are portions of two trainsbunning simultaneously. 7

Simultaneous burning of portions of "two trains is characteristic of manyaadjustments of-conventional time fuses and isrthereason Whysuch time fuses cannot be satisfactorily controlled, as to the pressureunder "which they burn, bymeans'ofa constantvent orifice.

"The manipulation in setting the time rings is familiar to'those skilled inithe :art, with the "exception of the details already pointed out, and'hence neednot bezfsurther described.

hat is claimed is: I

'1. The combination of amultiple time ring fuse constructed :and arranged to evolve powder gases *atwa constant time rate in all timing adjustments R thereof; and a constant 'area'throttlin'g orifice controlling the "discharge ofspowder gases. evolved by said fuse and so dimensioned as'toexert a constant back pressure thereon.

-2. The combination of a fuseincluding a plurality of uniform time-powder trains ar- 1 ranged to burn successively and: adjustable to'transmit theflame to the charge to-be ignited-at any point in the a ggreg'ate length of thetrains; and:a constant area throttling orifice controlling the discharge of powder gases evolved'by 'saidtrains and so dimensioned as to exert a constant back pressure thereon. a

3. The combination of a shell having. an explosive charge; a combined body :and timing ring member swiveled on said shell; a concussion "primer and a time arranged to be ignited thereby,

a second timing ring swiveled .on, said shell and adjustable relatively to said shell and to said combined member; and a time train in said second timing member adapted to be ignited by said first train and to transmit the flame to said charge.

4. l he combination of a shell having an explosive charge; a body member swiveled on said shell; a time powder train mounted to turn with said body member; a concussion primer mounted in said body member and arranged to ignite the powder at the beginning of said train; and a second timing member including a second time powder train adjustable relatively to said shell and to said body member, and serving in a given adjustment relatively to the shell to transmit flame to said charge directly from chosen points in the length of the first train according to the concurrent relative adjustment of the body member thereto, and serving in a given adjustment relatively to said body member to transmit flame to said charge from the end of said first train through chosen lengths of the second train according to the concurrent adjustment of the second timing member relatively to the shell.

5. The combination of a shell having an explosive charge; a body member sWiveled on said shell; a time powder train mounted to turn with said body member; a concussion primer mounted in said body member and arranged to ignite the powder at the beginning of said train; and a second timing member including a second time powder train adjustable relatively to said shell and to said body member, and serving in a given adjustment relatively to the shell to transmit flame to said charge directly from chosen points in the length of the first train according to the concurrent relative adjustment of the body member thereto, and serving in a given adjustment relatively to said body member to transmit flame to said charge from the end of said first train through chosen lengths of the second train according to the concurrent adjustment of the second timing member relatively to the shell; and pressure regulating means controlling the discharge of the gases evolved by the trains when burning.

6. The combination of a shell having an explosive charge; a body member swiveled on said shell; a time powder train mounted to turn with said body member; a concussion primer mounted-in said body member and arranged to ignite the powder at the beginning of said train; and a second timing member including a second time powder train adjustable relatively to said shell and to said body member, and serving in a given adjustment relatively to the shell to transmit flame to said charge directly from chosen points in the length of the first train according to the concurrent relative adjustment of the body member thereto, and serving in a given adjustment relatively to said body member to transmit flame to said charge from the end of said first train through chosen lengths of the second train according to the concurrent adjustment of the second timing member relatively to the shell; and a constant area throttling vent, so proportioned relatively to the nature of the gases evolved by the trains when burning, and relatively to the maximum atmospheric pressure, as to maintain a constant gas pressure on said trains.

In testimony whereof I have signed my name to this specification.

ALTEN S. MILLER. 

